First flight pilots said the take off weight is 630,000lb of which 130,000lb is fuel. Test flight is almost 4hr and pilots said they can fly another 8hr before landing. Granted that it was only flying at 200 knots, is there enough info to project the actual fuel burn of the 748?

Quoting OldAeroGuy (Reply 4):No, cruise fuel mileage will not be tested until basic airworthiness has been established.

Correct, the exact fuel mileage will be verified on N5017Q (RC521), the second 747-8F test aircraft.

"The second 747-8F (RC521) will join the flight test program as soon as RC501's work confirms the high- and low-speed configuration around mid-March. Painted identically to the first aircraft for the test program, RC521's principal task will be proving the General Electric GEnx-2B67 engines and fuel efficiency of the model measured during NAMS (nautical air miles) tests."

Quoting web500sjc (Reply 2):or did they just dump the rest
of the fuel before landing

I am no expert, but I do not think you can "plan" to dump fuel before take off, as part of your operation.
Environmental organizations and local government may have something to say about that!
That is pretty much an emergency procedure, not something you do just for the sake of it.

What I would like to know, how do they test the fuel dumping facility on a new aircraft?
On the apron?

### "I am always on the Run"###

"Failure is not an option, it comes standard in any Windows product" - an anonymous MAC owner.

You want early flights to be mid-CG and mid-weight...you want to be right in the heart of the flight envelope since at the edges there be dragons. The easiest way to move CG and weight around is fuel load.

Quoting alwaysontherun (Reply 7):I am no expert, but I do not think you can "plan" to dump fuel before take off, as part of your operation.

You can. Its done routinely on test flights.

Quoting alwaysontherun (Reply 7):What I would like to know, how do they test the fuel dumping facility on a new aircraft?

Now *that* would annoy the airport. This type of testing can be done in a fuel dock if you've got hoses to catch everything coming out of the jettison pipes, but that's a pain. It's a lot easier to just fly it.

Quoting alwaysontherun (Reply 7):Environmental organizations and local government may have something to say about that!
That is pretty much an emergency procedure, not something you do just for the sake of it.

If it's done at altitude, the fuel atomizes and evaporates before it hits the ground...okay, it might cause a localized area of smog on a sunny day

Wasteful? Yes. But it's gotta be tested before someone has to do it in reality...and when it's needed in real life, it might save a life or even an airframe (a poorly-executed overweight landing could be the end of an airframe).

Without any permission from local authorities or anything like that?
Now that really surprises me!
I work in an industry where every drop counts, literally!
You drop as much as 1 liter of hydrocarbon in the water and you may end up in court, depending on circumstances obviously!

That is interesting. I thought they would test that on the ground.

Quoting tdscanuck (Reply 9):This type of testing can be done in a fuel dock if you've got hoses to catch everything coming out of the jettison pipes

Something like that is what I had in mind.

Just to confirm this point: a test pilot can open up "the valves" anywhere, as long as it is at sufficient altitude.

Quoting KELPkid (Reply 10):okay, it might cause a localized area of smog on a sunny day

Is that all?

That is the good thing about this site, so much to learn!

### "I am always on the Run"###

"Failure is not an option, it comes standard in any Windows product" - an anonymous MAC owner.

Without any permission from local authorities or anything like that?
Now that really surprises me!

As far as I know, yes. It's possible that the companies that do it have discharge permits to specifically cover this, but I've never heard of that before. Keep in mind that you're not dumping liquid hydrocarbons on the ground or water...it all evaporates before it gets to the ground. All jets dump some hydrocarbon vapour due to incomplete combustion, so it's just a matter of degrees.

Quoting alwaysontherun (Reply 11):Just to confirm this point: a test pilot can open up "the valves" anywhere, as long as it is at sufficient altitude.

Yes but, as mentioned above, there may be some kind of blanket preauthorization paperwork that I don't know about. I do know that you can do this on tests without getting specific permission for each individual test.